\begin{tikzpicture}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(0:1.5){P}
    \tkzDefLine[perpendicular=through P,normed](O,P)  \tkzGetPoint{b}
    \tkzDefPointOnLine[pos=2.0](P,b)  \tkzGetPoint{B}
    \tkzDefPointOnLine[pos=2.0](B,P)  \tkzGetPoint{C}

    \tkzDrawCircle[thick](O,P)
    \tkzDrawPoint(O)
    \tkzDrawSegments(O,P  B,C)
    \tkzLabelPoints[left](O)
    \tkzLabelPoints[right](B,C,P)
\end{tikzpicture}

